I'm fixing a buddys 4 wheeler and found that it had a rusted out gas tank. theres one for a 85 on ebay, and it looks close, however not 100% sure on it. This is a four stroke 2x4 with racks not the R. Also honda wants $499 for one if they can get it...thats great.

 

I have both 85 and 86,both leak from rust,my Honda dealer offered me an after market from clark,plastis,for 150.00 bucks